Question: alternate start of Winter War

[Gridley]

How plausible would it be for the Winter War to start either much earlier (within days or at most a few weeks of the invasion of Poland) or much later (Spring/Summer 1940)?

Is there really any major factor driving the date other than Stalin's whim (within that range)?

What are the (reasonably likely to probable) consequences? With better weather, do the Soviets get further? How are Allied plans to intervene affected? What happens to the rest of Scandinavia?

PoD no earlier than mid-1939, please, and I'm looking for things more towards the high end of the probability scale rather than the low end.

 

[Karelian]

Your PoD is most likely a little too late to change anything.

Closest potential way to alter the starting date of upcoming Finno-Soviet conflict to a later date would be the situation where Finnish government complies with early Soviet demands that Boris Rybkin stated during the Sudeten Crisis.

After this Soviet Union would most likely treat Finland just like the rest of the breakaway Baltic republics, and invade them all at the same time in summer 1940 when rest of the world is unable to help.